Electrochemical behavior of a typical redox mediator on a modified electrode surface: Experiment and Computer Simulations

GAVILLAN ARRIAZU M.; PAZ ZANINNI V; GULOTTA FLORENCIA A.; ARAUJO VIRGINIA M.; PINTO O. A

SURFACE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 658 p. 15 - 21

0039-6028

This paper describes the study of a redox species electrosorption on a modifiedelectrode by experimental measurements and computer simulation. The propose modelis based on the fact that charges are transferred to the electrode when an electroactivespecies is adsorbed on its surface. The electrode surface is modified by the irreversibleadsorption of a non-electroactive species, which blocks a percentage of the adsorptionsites. Hence, the electroactive species can only be adsorbed on the surface vacancies,and, when this phenomenon occurs, interact laterally with the non-electroactive one.Lattice-gas models and Monte Carlo simulations in the Gran Canonical Ensemble areused. The analysis conducted is based on the study of adsorption isotherms andvoltammograms, for several values of energies and adsorption degrees of the nonelectroactivespecies. In the case of experimental measurements, an artificial clay(Laponite®) represents the non-electroactive species while the redox probe Fe(CN)64- is the electroactive one. The results obtained by the proposed model are compared withexperimental voltammograms.